Feed screw releasing means



Sept. 30, 1952 R GRAY E A 2,612,057

FEED SCREW RELEASING MEANS Filed NOV. 1, 1951 v 2 SHEETS-SHEET l Imnentors LANDON R. GRAY HARRY PJSM/T/i JR.

fitter neg 'S P 1 L. R. GRAY ET AL 2,612,057

FEED SCREW RELEASING MEANS SHEETS--SHEET 2 Filed Nov. 1, 1951 RAY Zinnentors AAA/00M E. 6 HARRY 2 9mm .JIZ.

(Ittonieg Patented Sept. 30, 1952 UNITED STATES PATENT OFFICE .'2;612,057 TRELEASING MEANS :Isandon Gr-ay, Manhattan Beach, :and :EHa-rry 1?. 'Smith, Jr... Log v.zAngreles, Calif iassignorsdo :Bichard.Sei1-ied,allaya del Rey, Calii.'. s mmon-November 1, 1951, serialiioizflffiidd "This "invention relates *to means for-releasing a :lead screw from operative "engagementwith a member that is brought to "adiusted'pos'ition'by said lead screw. The present invention is acontinuation-in-part of our gpendin'g application, serial' No. 1 82 928,"filed September '2, 1950.

While the present -invention may be used in other connections. it *is particularly adaptedwo be used in stretch formi-ng*machineswhete Opposed devices, on opposite ends or aba'se, are employed to'pullon the ends'o'f a work piecawhile simultaneously forming said workpi'ece over *a die. Considerable pull is. thereby, exerted on said devices -and, "in order thattheymay retain their adjusted positions on-the base during "the stretch-forming operation, they are a'iiixed to the base as'by keys-or the like. *Said pulling devices are usually quite large and too heavy'to be manu'ally moved to "adjusted position, and for :this' purpose-power driven ie'ad screws are used for effecting'longitudinartraverse or each said device to a desiredposition on the base.

Assuming that a key is used "to interlock each pulling device-and the machine base, :it -wi11be realized that such a 'key, in order to in "its keyways in the base and pulling device, mustbe'tsufficiently undersize of the keyways to *permit "of introductionan-d"removal as-adjustment is made. iiccordinglygwhile thekeys'hold-the-devices fixed on 'the'floase 'for all practical purposes, there is slight movement :o'fthe devices toward each other that is absorbed when the stretch-forming operation is instituted. Such "a movement'would create a stress on the lead screws-where *the same are engaged withthe -'=pul1ing devices and may icause'the threads of saidscrews-tobreak'orto become so fatigued that rapid deteriorationwould :result.

Accordingly, it "is =an-object "oi the present invention to provide novl-andimproved*meansior releasing a'ieed 'oradjusting meniber from'forces that applied to a-device'that is fed-or adjusted by said memberso that said forces may betaken only by means *provided ior -such purmote.

Another object of the invention is to provide emeans as above indicated that entails movement sol-retraction of an element'relative to the feed or adjusting member, and carried by the device, :to a :position in which'the'forces on the device aarezinefiective on the feeder adjusting member.

s Another-object of the invention is to provide, :-'in means :of the character indicated, a nut for the .ieed or adjusting member havingoperative engagement with the device, said-nut *beingmovis released-from th "force 2 able relative to both the device and the feedzand adjusting member to release the latterftmm forcestending to move thedevice. a

.A iur'therobjec't of the invention is to provide, in "means as indicated, an e'lement'thatinter ieres withthe insertionof means for taking the thrust or '"force on said device' unless the nut is moved to release the feed or adjusting memberirom such thrust or .force, thereby assuring such release? The invention also has for its obiectsto pro-v ide such means that are "positive =in =operation. .0011 venient in we, easily installed in -a workingposition and easily disconnected"therefrom ri;economical of manufacture, relatively"simplepandmf generalrsuperiority and serviceability.

v The invention also comprises novel detaiiisvo-f construction and novel combinations-and arra-ngements of parts', whichwvill"moredullyappear in the course of'the'following description I However, the drawings merely show and the f-ollowing description merelydescribes embodiments of the :present invention, which are gi-ven ioy-"-way=-,o'i Iillustra'tion or example only.

' In the drawings, like reference charaeters' designate 'similarparts' in the several views. i

Fig. 1 is a iront elevational view or an arm of a stretch-forming"machineshowing a preferred form of .the present invention app'lied thereto.

Fig. .2 is an "enlarged detaiilview, partly iii section, showing the present. means in the position of the parts atthe end of "the: adj ustment :movement. "Fig. '3 is ajs'imilar View showing the operative position wherein the 'feed or adjusting member of astretch f orming operation. 1

Fig. '74 is :avertical SBCtiOIlBfl view-as *taken on lined- 10i Fig; 3. Fig.2: is a view similar to Figfid o'f aimodifica' said bracket as *omapivot-H', said tylinder-iraving a piston therein, and said-piston fhay'ing 15a piston rod I 5 --extending iromone end of thescylfinderand-carminga'chuck 0r the 111E616- f I '65 *Inpractice, assembly l lismositionedalong'fthe in a selected keyway of a series of keyways 2| provided in arm top I I.

It will be clear that admission of fluid to each cylinder l3 of the opposedassemblies II and in the ends thereof that cause retraction of rods I5,

will pull the chucks I6 apart and exert a stretch force on work-piece I8. I brackets I2 are pulled toward each other by such force and said pull is resisted by key is. Since said keys are slightly under-size of the keyways, they fit in order to be readily inserted and re.- moved when adjustment of assemblies II is desired, the first result of a stretch-forming pull is a slight movement of brackets I2 toward each o her. When he. k ys take hold, such movement stops and, for all practical purposes, the brackets l2 are firmly afllxed to arms I0 during a stretchforming operation.

In the present case. a lead screw 22, mounted betweenbearings 23 and 24 onarm It, constitutes themeans for adjusting assembly I 2 along top IT. The power for-rotating the screw comprises an electricmotor 25'ancl a reducing gear 25 interconnecting the-motorand the screw for relatively slow rotation of the latter. Motor 25 is of th reversing typeso that the screw may be rotated in either direction, as desired.

According to the invention, means 21 is provided to operatively interengage'bracket l 2 of assembly I I and feed screw 22. In Figs. 1 to 4, said means 21 comprises a bracket 28 aifixed to bracket I2 and having spaced depending walls 29 apertured at 30 to freely pass screw 22. Aplate 3! connects the free ends of walls 28 to render them rigid. A nut 32 is engaged with screw 22 and resides in the space between bracket walls 29, the width of the nut being substantially less than the space between walls 23, thereby allowing for traverse 0f the nut from positions abutted against either wall 29 to a position intermediate and spaced from said walls. The nut is held against rotation by sliding engagement with plate 3i. In practice, bracket 28 is-vertically aligned with keyway 20 sothat nut 32 is substantially centered on said keyway when in the mentioned intermediate position. An upstanding plate member. 33 is secured to said nut and the upper end 01 said member is formed with a bifurcation somewhat largerthan the lower portion of keyway 2!! and in register therewith only when the nut 32 is in said intermediate position. I

Fig. 3 shows the normal position in-whichthe bracket I2 is subject to pull relative to base arm I0. Q When it is desired to change the position of said bracket and assembly II to another part of said arm, key I9 is pulled through bifurcation 34. Motor 25 is started to rotate screw 22 in a direction'to move assembly II tothe left or right sesame ass t a 3 s o i t e. iitem Consequently, the

abutted against wall 29, but bifurcation 34 is out of register with keyway 20. Therefore, it is not possible to re-insert key I9 to lock assembly II to arm I0. By rotating feed screw 22 in the opposite direction to bring nut 32 to the intermediate position of Fig. 3, said keyway 20 and bifurcation 34 are re-aligned and key I9 may be slid into place.-

-In the above manner, assurance is had that the thrust on bracket I2 cannot be transmitted to nut 32 to cause mutilation or other damage to the threads of screw 22. Thus, the purposes of the invention are accomplished by releasing the screw from the forces or thrust on bracket I2 thatseek to move said bracket along arm I0.

- Key [9 alone, or comparable locking means, serves 7 to absorbsuch thrust.

In Figs. 5 to '7, means 2'1 comprises a bracket j- 35 afiixed to bracket [2 and having spaced depending walls 36 in which bearings 31 freely pass feed screw 22.-v Front and back plates 38 connect said wallsto renderv them rigid. In this case, a half nut 39 is disposed between walls 36 and the width. of said half nut is substantially less than the space between said walls.

Half nut 39 is mounted below feed screw-22 and is held against rotation by guiding engagement with walls 38. An eccentric cam 40 extends be: tween walls 38and is carried by a pin 4i extending through and between said wa11s.- A pair of straps 42, trained around cam 43 and having their ends connected to thehalf nut, operatively connect said half nut to said cam, the connection being a sliding one as well as one that movesthe half nut toward and away from screw 22 when said cam is rotated on pin 4|. An elongated handle 43, terminating in a knob 44, is provided for manipulating cam 48. v Fig. 5 corresponds to Fig. 3 and. is the normal position in .which. bracket I2 is subject to pull relative to base arm Ill. It willbeclear that, after key I9 is pulled and'screw 22 started rotating, handle 43 is pulledup as in Fig, "7, to cause cam 40 to push thehalf nut 39 into engagement with the rotating feed screw.- ;Here-also,. the nut first slides into abutment with-one wall SG-andthen pushes against said wall to effect traversing movement of bracket l 2 and assembly I carried there? by. When register of keyway 20 i achieved with a selective keyway 2| on base arm I 0, handle 431s released orpushed down, causing strap 42-to'pull the halfnut free of screw 22. Said screw may continue to rotate until stopped-but key I9 may now be slid into place with assurance that the half nut, while still abutting one wal136, cannot transmit the thrust on bracket I 2 to the threads ofscrew 22. 3 H p j.

While the i vention that has been illustrated and described is nowregarded as the'preferred embodiments, the constructions: are; of 7 course, subject tomodificationswithout departing from the spirit and scope of the invention; It istherefore not desired 1to=restrict the'invention to'the particular .forms oiiconstruction' illustrated: and described, "but to cover all modifications. that may .fall within the scope of the appended claims. l-laving thus describedtthe invention, what is 0181311518; and. q sire d t o :be secured by Letters Paten.s:......'..

1,.; In astructure-having abase provided with a plurality of keywaysand having a memberr p vided with a keyway adapted to register with a e e e ne of said-plurality'of keywaysand idlr i tere e way being receptiveiof a key 0, l k-$116 member to the base against a thru t ment and the member along the base to effect the mentioned register of keyways, said element being subject to the thrust on said member when abutting said abutment, and means to move said element to release the same from the force of said thrust.

2. In a structure according to claim 1: the feed device comprising a lead screw and the element engaged therewith comprising a non-rotational nut movable by rotation of said lead screw;

3. In a structure according to claim 1; the feed device comprising a lead screw and the element engaged therewith comprising a non-rotational nut movable by rotation of said lead screw, and the means to move said nut element to release position comprising motive power to rotate the lead screw in a direction to move said nut element to a position spaced from and intermediate the pair of walls.

4. In a structure according to claim 1: the feed device comprising a lead screw and the element engaged therewith comprising a non-rotational nut movable by rotation of said lead screw, and the means to move the nut element to release position comprising a manually operable eccentric cam carried by said pair of walls and rotationally and slidingly connected to the nut element.

5. In a structure having a base provided with a plurality of keyways and having a member provided with a keyway adapted to register with a. selected one of said plurality of keyways and said registered keyways being receptive of a key to lock the member to the base against a thrust on the member, a lead screw carried by thebase, a nut engaged with the lead screw and movable therealong, a pair of abutments secured to the member, one on each side of the nut, and spaced apart a, distance greater than the length of the nut, the nut, during rotation of the lead screw, first abutting one abutment of said pair of abutments and then moving said abutment and. the member along the base to effect the mentioned register of keyways, said nut being subject to the thrust on saidmember when abutting said abutment and, thereby, subjecting the threads oi'the lead screw to said thrust, and motive power means to rotate the lead screw in a direction to back the nut away from the abutment which it abuts to a position where the same is released from said thrust.

7 her and through which the lead screw extends, a

6. In a structure according to claim 5: an element fixed to the nut and movabletherewith, said element being provided with a bifurcation in register with the keyway in the device only when the nut is in the backed ofi position.

'7. In a structure having a base provided with a plurality of keyways and having a member provided with a keyway adapted to register with a selected one of said plurality of keyways and said registered keyways being receptive of a key manually operable eccentric cam carried by said pair of abutments and in spaced relation to the lead screw, and a half nut disposed between said pair of abutments and connected to the eccentric cam, slidable relative thereto, and movable by said cam into and out of engagement with the lead screw, said half nut, when moved by the cam to a position disengaged from'the lead screw, releasing said lead screw from the thrust on the member.

8. In a structure having a base provided with a plurality of keyways and having a member provided with a keyway adapted to register with a selected one of said plurality of keyways and said registered keyways being receptive of a key to lock the member to the base against a thrust on the member, a lead screw carried by the base, a pair of spaced abutments secured to the member and through which the lead screw extends, a manually operable eccentric cam carriedby said pair of abutmentsv and in spaced relation to the lead screw, and a half nut disposed between said pair of abutments and connected to the eccentric cam, slidable relative thereto, and movable by said cam into and out of engagement with the lead screw, the pair of abutments being spaced apart a distance greater than the length of the half nut, said half nut, when moved to engaging position with the lead screw first being moved by the latter to abut one of said pair of abutments and then moving said abutment and 1 members to effect the mentioned register of keyways, said half nut being subject to the thrust on said-member when abutting said abutment and, thereby, subjecting the threads of the lead No references cited. 

